Adults are small (up to 2.5 mm long) and are shiny black, while the nymphs are slate grey.
Recorded on all winter pulses in Australia, and is also found on many other legume and non-legume plants. Mungbeans are particularly attractive hosts.
Cowpea aphids inject toxins into the plant while feeding; they most likely reduce mungbean vigour and yields. Aphid-feeding also produces honeydew, which grows sooty mould that reduces photosynthesis and makes harvesting difficult.
Cowpea aphid can cause damage as a vector of virus diseases in winter pulses in southern Australia. Cowpea aphids may contribute to poor productivity of medic pastures in dry years.